1. Field of the Invention
The present invention relates to a control element having a rotary knob, a rotating axle, and a detent device that includes a gear pump, which is integrated into the cross-section of a channel, by which a magnetorheological fluid is pumped by the gear pump through the channel when the rotary knob is rotated.
2. Description of the Background Art
DE 199 64 133 A1 discloses a rotary switch or rotary control that meets so-called knob impact criteria and has a wiper plate on the lower part of its rotary knob. The corresponding signals are sensed by contact springs on a base plate. This makes it possible for the operational control to be continuously rotated. The detent is produced by a lateral knurled wheel.
Another known detent element is sliding detent springs such as are frequently encountered in potentiometers. Also known are rotary controls based on the principle of magnetic field change, such as are described in EP 0 780 852 B1, for example.
Known from DE 100 29 191 A1 is an electronically controlled rotary fluid knob as a haptic control element. In one of the example embodiments, the rotary control has a laminated stator part that is made of soft magnetic material, carries an armature winding and generates a radial magnetic field in a magnetically active gap between the stator part and another stator part. Located in this gap is an annular, nonmagnetic rotor, which is connected by a shaft to a bell-shaped rotary knob. Also located in the gap is a magnetically active fluid. The rotary knob can be braked with differing intensity and duration depending on whether a stop is to be simulated or a detent is to be felt. When the user turns the rotary knob, a perception of alternating positive and negative acceleration is produced for the user, which corresponds to the haptic feel of a detent. PWM control of the coil is preferred. In addition, an algorithm for haptic representation of a programmable stop is described. The rotational position of the rotor is converted into a signal representing the angle of rotation by a sensor for measuring the angle of rotation.